I am not sure if I am doing something wrong, but when I encode an ac3 5.1 channel to 2 channel I have errors using azid to encode it to mp2. I dont have this problem when encoding (changing bit rate) to 5.1 again, but once I go to 2 channel, surround or stereo, I have problems encoding it into mp2 via azid. I cant say its a bug, as I have just started using ac3enc, but I would like some input on what I can do to avoid this error: "E33: Illegal symmetric 7-level value =7"

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Here is the log from the 5.1 to 2 channel encode:

I dont post much here, but I do read the faq's and I hope I didn't miss something on the forum that could have resolved this, and if I did, in advance, im sorry for wasting your time. Ultimately, I was just wondering if I did something wrong, or if others have had the same problem

@fuct
I have the same problem when encoding to 384/448kbps AC3...
additionally:
.)'PX3x->WAV Converter' / WinDVD produces short gaps/clicks.
.)My standalone (JVC) drops both audio and video frames switching to the ac3enc.dll-produced language track.
...for me it seems to be a common problem

@DSPguru
'... because you could use anything else (mp2/mp3/ogg),...'
Does it mean i can mix e.g. 2xAC3 + 1xMP2 streams into one VOB?

I apologize to the mods for this cross-post, but judging from the big Goose Egg I've gotten in replies in DVD authoring, I think maybe the readers of this forum might be a better help. I tried a search but all I found was the well-known AC3enc "volume bug". Anyways....

I'm having a problem with my sound. I was taking an old divx recording and turning it into DVD. I used TMPGEnc to encode the video, but everything I've read said not to do the sound in it, so I transcoded the MP3 of the audio track (48 KHz 2 channel stereo track, originally AC3) back to AC3 using AC3Machine/BeSweet - no errors reported in the logfile. The AC3 plays in Win Media Player without a problem, but it won't play in PowerDVD. Actually, it will play, but there's no sound, even with the volume cranked to maximum - PowerDVD doesn't report any errors with the file either, just doesn't actually play any sound. I thought maybe it didn't support separate AC3 files (it says it does but you never know), so I proceeded with the authoring anyway.

I did all the "fun" stuff in SpruceUp (full version) - menus, etc. etc. SpruceUp imported the video file and seemed to successfully import the audio file as well (the little speaker symbol on the clip asset was present). When I compiled the disk image for burning, no errors were reported. But when I played the image in PowerDVD it still had no sound. So I used DVD Decrypter to extract the AC3 from the new disk image, and it extracted the stream successfully, including playing it again using WMP. Just as another test, I took a DVD from my collection and it played normally using PowerDVD. It had the same kind of AC3 format/bitrate as the one I encoded that didn't work.

So does anyone know where the kink is in all this? Why am I not getting sound in PowerDVD with that particular file, when other programs will play it? I'm at a loss right now, and I don't want to burn a DVD until I find out the problem - I'm inexperienced, but not stupid .

Any help is appreciated, thanks!

QUICK UPDATE: I used the AC3 I ripped from my "working" DVD - the one from my collection - and ran it through Azid/BeSweet (1.5b21 for one try, then 1.4 for a second try, same results) via Gordian to turn it into an MP3. The MP3 played in Sonique normally. I then took the MP3 and ran it back through BeSweet via AC3Machine as I did the first one, and it too stopped working in PowerDVD after that (but still works in WMP). I have all the filters (using AC3filter), have removed Morgan Stream Switcher, updated and downdated BeSweet, and I'm now at a total loss. Is there any other way to re-encode the AC3? Is there a way to set the byte order if that's the problem? I'm so....

Here's the BeSweet Logfile in case something in the command line sticks out as a problem:

I was toying around with my T3 dvd, converting from ntsc to pal and when i was transcoding the 2 directors commentary with ac3machine i noticed some weird things, like: ac3machine dont give a damn what i check in or out, except changing the bitrate setting.. It always wanted to encode in 5.1, no matter what.. :-/ Maybe im just a b-a-d lama but after searching the forums i havent find anything similar. On the other hand I had _never_ have a low volume ac3 with ac3machine..

Logfiles: (settings were the same for both ac3 streams! then whats with the downmix thingy in the second?)

I believe I have run across a small problem with ac3enc.c in version 0.4.8 of ffmpeg which causes it to generate an AC3 bitstream which is not quite compliant with the spec. The problem originates in
compute_bit_allocation(), which computes how much of an AC3 frame is
available for the actual data.

Quote:

I have seen some high-end hardware DVD players which get upset when they see this bit set to 1: they then believe that auxiliary data is present, will try to decode this nonsence data, and you end up with a corrupted audio signal and with the player trying to sync up video to that corrupted audio (i..e the picture jumps forward).

Quote:

With these two changes, the DVD player is no longer having problems with the AC3 bitstream generated by ac3enc.c

Could this be the fix people have been looking for? Could the mean a return to the BeSweet fold?

"due it its suckness" (how do I translate that?!) you didn't support AC3ENC anymore; although it was not that easy to collect really objective facts about which kind of bugs it contained, at least I understood that {sometimes..often} the resulting file was not normalised and amplified correctly.

Now, according to this message (ffmpeg CVS 2004-02-26), there is a fix available, which is already used in ffmpegGUI beta build 3. You can read reports about the tool in the DVDRHelp forum. So I wonder if you have the mercy to re-support AC3ENC if this patch fixes that mentioned bug, or if you have some other AC3 encoder project as substitute in mind...

"due it its suckness" (how do I translate that?!) you didn't support AC3ENC anymore; although it was not that easy to collect really objective facts about which kind of bugs it contained, at least I understood that {sometimes..often} the resulting file was not normalised a

I think he meant "due to its suckness"

Anyway, this is the only free AC3 encoder available, and Besweet is the most versatile audio-conversion/resampler/etc around. If there's this patch available, it should be given a chance, at the very least.

you guys gotta remember, when some people use the ac3 encoder and *if* its quality isnt top notch, or some other bug shows up, they will complain to dspguru about it all. look how many posts are about the ac3enc not working which amounts to people not bothering to read thier log files and that just proves that point.

if it is added, it should be added to a specially marked version that screams at people *not* to use it for anything at all other then testing. but personally, i would love to give it a try again out of sheer curiousity.

It's not that terribly difficult to compile yourself, when I need Ac3 (which I avoid like the plague), I just download the latest version of ffmpeg and recompile......IMHO BeSweet should probably have an "Ac3(experimental)" option to make you think twice. Then when it reaches a stable point add it into BeSweet...anyways that's my two cents

Well, can you compile it in VC++? That's a bit harsh, and Besweet is maioritarilly for Windows users. I dont know how to use gcc/mingw, so a pre-compiled build of the dll for Win32 would be very handy.

FYI, apparently the changes made in ac3enc.c were in the program stream to make the parts ac3-standards compiant. I donwnloaded the ffmpeg 0.4.8 and compiled it exactly the way it was. I then downloaded the latest version of ac3enc.c, ac3dec.c, ac3tab.h, and ac3.h. "diff" showed that the version on 0.4.8 was the same as the CVS version, so I pulled up the thread again and manually programmed in the C code that he reccomended be changed. I compiled the new version also. I renamed them to "ffmpego.exe" and "ffmpegn.exe" and encoded a short WAV file at 48kHz. both ac3 files ended up EXACLY the same size (bit for bit), however, when "diff" compared them, it said "Binary files 131n.ac3 and 131o.ac3 differ". So apparently there is a difference. Someone has mentioned that hardware players don't complain with this new method.

Anyways something to think about

p.s. I made the binaries available, but please note that:
a) I'm not liable for anything that happens
b) The few changes made have not yet been officially endorsed by Fabrice Bellard

That said, I would like to hear if it preforms better than the last compile.